1. Field of the Invention
The present invention relates generally to an ad-hoc network. More particularly, embodiments of the present invention relate to a system and method for setting a route among nodes that constitute an ad-hoc network.
2. Description of the Related Art
Generally, a mobile communication system transmits/receives data between a mobile terminal and a base station. That is, the mobile terminal and the base station directly transmit/receive data to/from each other without passing data through other nodes. However, an ad-hoc network uses other nodes when it transmits data from a source node to a destination node.
In order to transfer data (packets) to the destination node in an ad-hoc network, the source node first sets a route. A route is a path through which the data packets are transmitted. Using the set route, the source node transmits the data to the destination node. However, the nodes that constitute the ad-hoc network guarantee the network's mobility. Accordingly, if any of the nodes moves, the route should be set again. The term “constitute” as it is used throughout this disclosure is intended to be open ended. Accordingly, the ad-hoc network may include additional components. Hereinafter, methods for setting a route in an ad-hoc network will be explained.
A method for setting a route may be classified as a proactive method or a reactive method. According to a proactive method, every node that constitutes the ad-hoc network stores a routing table. Accordingly, if packets to be transmitted are generated, the node transmits the packets without delay using the routing table. Meanwhile, the respective node has routing information of other nodes that constitute the ad-hoc network, thus if one node moves, all nodes update their routing tables by transmitting/receiving control information. Additionally, as the number of nodes that constitute the ad-hoc network increases, both the size of the routing tables and the amount of control information being transmitted/received increase abruptly.
The reactive method is a method for setting a route only when needed. Specifically, a node that does not presently take part in packet transmission does not have a routing table, and does not generate control information even if it moves. However, if packets to be transmitted are generated, a route for transmitting the packets should be set. Accordingly, it takes a lot of time to transmit the generated packets. Additionally, as the number of generated packets increases, i.e., as the amount of control information for setting the route increases, the load of the ad-hoc network also increases. Accordingly, a scheme for rapidly transferring the generated packets with mobility of nodes guaranteed is required.